CivilBay                          
                             
 Home  > Concrete  > Concrete Anchorage  > Anchor Stud Design With Tension, Shear and Moment Using Anchor Reinforcement
                                       
Skip Navigation Links                     ToolTip :  Login

                   
STUD ANCHOR DESIGN Combined Tension, Shear and Moment

Result Summary                  
Anchor Rod Embedment, Spacing and Edge Distance       OK  
Min Rquired Anchor Reinft. Development Length ratio = 0.87 OK  
Overall         ratio = 0.98 OK  
Seismic Design         Tension =   OK  
          Shear =   OK  

Design Code Reference                  
Welded stud design based on                 Code Abbreviation
ACI 318-11 Building Code Requirements for Structural Concrete and Commentary Appendix D ACI 318-11
PIP STE05121 Anchor Bolt Design Guide-2006 PIP STE05121
                Code Reference
Welded Stud Data                    
Factored moment Mu = [kip-ft]            
Factored tension or compression Nu = [kips] in compression    
Factored shear force Vu = [kips]      
                   
 
                     
No of bolt line for resisting moment =            
No of bolt along outermost bolt line =            
                   
Outermost bolt line spacing s1 s1 = [in] 3.00   OK   Page A -1 Table 1
Outermost bolt line spacing s2 s2 = [in] 3.00   OK    
                     
Column depth d = [in]            
                     
Concrete strength f'c = [ksi]    
Welded stud material   =          
Anchor tensile strength futa = 65.0 [ksi]         ACI 318-11
      Anchor is ductile steel element       D.1
Welded stud diameter da  = [in]            
Anchor effective cross section area Ase = 0.442 [in2]        
Welded stud head bearing area Abrg = [in2]          
                   
Welded stud embedment depth hef = [in] 9.00   OK   Page A -1 Table 1
Pedestal height ha = [in] 17.00   OK    
Pedestal width bc = [in]          
Pedestal depth dc = [in]          
                   
                  PIP STE05121
Welded stud edge distance c1 c1 = [in] 4.50   OK   Page A -1 Table 1
Welded stud edge distance c2 c2 = [in] 4.50   OK    
Welded stud edge distance c3 c3 = [in] 4.50   OK    
Welded stud edge distance c4 c4 = [in] 4.50   OK    
                   
                  ACI 318-11
To be considered effective for resisting anchor tension, vertical reinforcing bars shall be located RD.5.2.9
within 0.5hef from the outmost anchor's centerline  
Avg ver. bar center to anchor rod center distance dar = [in]  
No of ver. rebar that are effective for resisting anchor tension nv =    
Ver. rebar size No. = 1.000 [in] dia single rebar area As = 0.790 [in2]  
Ver. rebar top anchorage option        
                  ACI 318-11
To be considered effective for resisting anchor shear, hor. reinft shall be located RD.6.2.9
within min( 0.5c1, 0.3c2 ) from the outmost anchor's centerline min (0.5c1, 0.3c2) = 1.50 [in]  
           
No of tie leg that are effective to resist anchor shear nleg =    
No of tie layer that are effective to resist anchor shear nlay =    
Hor. tie rebar size No. = 0.500 [in] dia single rebar area As = 0.200 [in2]  
For anchor reinft shear breakout strength calc    
                   
Rebar yield strength - ver. rebar fy-v = [ksi]        
Rebar yield strength - hor. rebar fy-h = [ksi]        
Total no of welded stud n =          
No of welded stud carrying tension nt =          
No of welded stud carrying shear ns =          
                 
                     
                 
For side-face blowout check use                
No of welded stud along width edge nbw =          
                  ACI 318-11
Provide built-up grout pad ?   =           D.6.1.3
                   
Seismic design category SDC >= C   =           D.3.3.1
Welded stud load E <= 0.2U Tensile =   Shear =   D.3.3.4.1 & D.3.3.5.1
Welded stud satisfies opion Tensile = Shear = D.3.3.4.3 & D.3.3.5.3
                   
Strength reduction factors                 ACI 318-11
Anchor reinforcement fs = 0.75           D.5.2.9 & D.6.2.9
Anchor rod - ductile steel ft,s = 0.75   fv,s = 0.65   D.4.3 (a)
Concrete - condition A ft,c = 0.75   fv,c = 0.75   D.4.3 (c)

CONCLUSION
                 
Anchor Rod Embedment, Spacing and Edge Distance       OK ACI 318-11
Min Rquired Anchor Reinft. Development Length ratio = 0.87 OK 12.5.1
Overall ratio = 0.98 OK  
Tension          
Anchor Rod Tensile Resistance ratio = 0.38 OK  
Anchor Reinft Tensile Breakout Resistance ratio = 0.15 OK  
Anchor Pullout Resistance ratio = 0.48 OK  
Side Blowout Resistance ratio = 0.37 OK  
Shear          
Anchor Rod Shear Resistance ratio = 0.33 OK  
Anchor Reinft Shear Breakout Resistance          
      Strut Bearing Strength ratio = 0.54 OK  
      Tie Reinforcement ratio = 0.69 OK  
Conc. Pryout Not Govern When hef >= 12da       OK  
Tension Shear Interaction          
Tension Shear Interaction ratio = 0.98 OK  
           
Seismic Design         ACI 318-11
Tension Applicable       OK D.3.3.4
Seismic SDC>=C and E>0.2U , Option D is selected to satisfy additional seismic requirements as per D.3.3.4.3    
                   
Shear Applicable       OK D.3.3.5
Seismic SDC>=C and E>0.2U , Option C is selected to satisfy additional seismic requirements as per D.3.3.5.3    

Assumptions ACI 318-11
1. Concrete is cracked D.5.2.6, D5.3.6, D.6.2.7
2. Condition A - supplementary reinforcement is provided D.4.3 (c)
3. Load combinations shall be per ACI 318-11 9.2 D.4.3
4. Anchor reinft strength is used to replace concrete tension / shear breakout strength as per D.5.2.9 & D.6.2.9
    ACI 318-11 Appendix D clause D.5.2.9 and D.6.2.9  
5. For tie reinft, only the top most 2 or 3 layers of ties (2" from TOC and 2x3" after) are effective  
6. Strut-and-Tie model is used to anlyze the shear transfer and to design the required tie reinft  
7. For anchor group subject to moment, the anchor tensile load is designed using elastic analysis D.3.1
     and there is no redistribution of the forces between highly stressed and less stressed anchors  
8. For anchor tensile force calc in anchor group subject to moment, assume the compression  
     resultant is at the outside edge of the compression flange and base plate exhibits rigid-body  
     rotation. This simplified approach yields conservative output  
9. Anchor reinft used in structures with SDC>=C shall meet requirements specified in D.3.3.7 D.3.3.7

CACULATION                  
Anchor Tensile Force                  
Single bolt tensile force T1 = [kips] No of bolt for T1  nT1 = 2.0    
Sum of bolt tensile force Nu = S ni Ti     = 16.48 [kips]  
                   
Anchor Rod Tensile Resistance                 ACI 318-11
  f t,s Nsa = f t,s Ase futa = 21.55 [kips] D.5.1.2 (D-2)
  ratio = 0.38 > T1 OK  
               
Anchor Reinft Tensile Breakout Resistance       ACI 318-11
Min required full yield tension ldh ldh = 180 degree hook case = [in] 12.5.2, 12.5.3(a)
Actual development lenngth la = hef - c (2 in) - dar x tan35 = [in]  
        > 8.00 OK 12.5.1
             
              ACI 318-11
Anchor reinft breakout resistance fs Nn = fs x fy-v x nv x As x (la / ld , if la < ld) = 112.30 [kips] D.3.3.4.5, D.5.2.9, 12.2.5
  ratio = 0.15 > Nu OK  
               
Anchor Pullout Resistance             ACI 318-11
Single bolt pullout resistance N p = 8 Abrg fc' = 32.66 [kips] D.5.3.4 (D-14)
  ft,c Npn = f t,c Ψc,p Np = 22.86 [kips] D.5.3.1 (D-13)
  Ψc,p = 1 for cracked conc       D.5.3.6
  f t,c = 0.70 pullout strength is always Condition B D.4.3(c)
Seismic design strength reduction   = x 0.75 applicable = 17.14 [kips] D.3.3.4.4
  ratio = 0.48 > T1 OK  
               
Side Blowout Resistance              
Failure Along Pedestal Width Edge             ACI 318-11
Tensile load carried by anchors close to edge which may cause side-face blowout        
along pedestal width edge Nbuw = nT1 x T1 = 16.48 [kips] RD.5.4.2
  c = min ( c1, c3 ) = 5.00 [in]  
  s = s2 = 16.00 [in]  
Check if side blowout applicable hef = 14.00 [in]          
    > 2.5c side bowout is applicable D.5.4.1
Single anchor SB resistance ft,c Nsb = = 38.33 [kips] D.5.4.1 (D-16)
Multiple anchors side blowout              
      work as group ftcNsbgw = (1+s/ 6c) x ft,c Nsb = [kips] D.5.4.2 (D-17)
Seismic design strength reduction   = x 0.75 applicable = 44.08 [kips] D.3.3.4.4
  ratio = 0.37 > Nbuw OK  
               
Group side blowout resistance ftc Nsbg =   = 44.08 [kips]  
               
Govern Tensile Resistance Nr = min ( f nt Nsa, f Nn, f nt Npn, f Nsbg ) 34.29 [kips]  
               
Anchor Rod Shear Resistance             ACI 318-11
  f v,sVsa = f v,s ns Ase futa = 74.70 [kips] D.6.1.2 (a) (D-28)
Reduction due to built-up grout pad   = x 1.0 , not applicable = 74.70 [kips] D.6.1.3
  ratio = 0.33 > Vu OK  
               
Anchor Reinft Shear Breakout Resistance       ACI 318-11
Strut-and-Tie model is used to anlyze the shear transfer and to design the required tie reinft  
STM strength reduction factor fst = 0.75       9.3.2.6
               
        
               
Strut-and-Tie model geometry dv = 2.250 [in] dh = 2.250 [in]  
  θ = 45    dt = 3.182 [in]  
Strut compression force Cs = 0.5 Vu / sinθ = 17.68 [kips]  
               
Strut Bearing Strength             ACI 318-11
Strut compressive strength fce = 0.85 f'c = 4.4 [ksi] A.3.2 (A-3)
               
* Bearing of welded stud              
    Anchor bearing length le = min( 8da , hef ) = 6.00 [in] D.6.2.2
    Anchor bearing area Abrg  = le x da = 4.50 [in2]  
    Anchor bearing resistance  Cr = ns x fst x fce x Abrg = 59.67 [kips]  
        > Vu OK  
* Bearing of ver reinft bar              
   Ver bar bearing area Abrg  = (le +1.5 x dt - da/2 -db/2) x db = 9.90 [in2]  
   Ver bar bearing resistance  Cr = fst x fce x Abrg = 32.81 [kips]  
   ratio = 0.54 > Cs OK  
               
Tie Reinforcement              
* For tie reinft, only the top most 2 or 3 layers of ties (2" from TOC and 2x3" after) are effective
* For enclosed tie, at hook location the tie cannot develop full yield strength fy . Use the pullout resistance in
    tension of a single hooked bolt as per ACI 318-11 Eq. (D-15) as the max force can be developed at hook Th
* Assume 100% of hor. tie bars can develop full yield strength
 
Total number of hor tie bar  n = nleg (leg) x nlay (layer) = 4    
              ACI 318-11
Pull out resistance at hook Th = ft,c 0.9 fc' eh da = 3.95 [kips] D.5.3.5 (D-15)
  eh = 4.5 db = 2.250 [in]  
               
Single tie bar tension resistance Tr = fs x fy-h x As = 9.00 [kips]  
               
Total tie bar tension resistance fsVn = 1.0 x n x Tr = 36.00 [kips] D.3.3.5.4 & D.6.2.9
  ratio = 0.69 > Vu OK  
               
Conc. Pryout Shear Resistance              
The pryout failure is only critical for short and stiff anchors. It is reasonable to assume that for general
cast-in place headed anchors with hef > = 12da , the pryout failure will not govern
               
  12da = 9.00 [in] hef = 14.00 [in]  
        > 12da OK  
               
Govern Shear Resistance Vr = min ( fv,sVsa , fsVn ) = 36.00 [kips]  
               
Tension Shear Interaction             ACI 318-11
Check if Nu >0.2f Nn and Vu >0.2f Vn = Yes       D.7.1 & D.7.2
      Nu / f Nn + Vu / f Vn = 1.18   D.7.3 (D-42)
  ratio = 0.98 < 1.2 OK  
               
Seismic Design              
Tension     Applicable     OK  
Option D is selected. ACI 318-11
User has to ensure that the tensile load Nu user input above includes the seismic load E, with E increased
by multiplying overstrength factor Ωo
D.3.3.4.3(d)
                   
Seismic SDC>=C and E>0.2U , Option D is selected to satisfy additional seismic requirements as per D.3.3.4.3    
               
Shear     Applicable     OK  
Option C is selected.             ACI 318-11
User has to ensure that the shear load Vu user input above includes the seismic load E, with E increased
by multiplying overstrength factor Ωo
D.3.3.5.3(c)
               
Seismic SDC>=C and E>0.2U , Option C is selected to satisfy additional seismic requirements as per D.3.3.5.3    
                   

ToolTip